Coolant system for machine tools

Abstract

A coolant system for machine tools, includes a pump ( 12 ) for the coolant, at least one consumer ( 10 ), a pressure sensor ( 24 ) for detecting an actual pressure (P i ) in the coolant system, a feedback control device ( 22 ) acting upon the pump ( 12 ) for regulating the pressure in the coolant system to a target pressure (P s ), and a limiting valve ( 26 ) for limiting the pressure of the coolant supplied to the consumer, wherein in that the opening pressure (P lim ) of the limiting valve ( 26 ) is variable and the feedback control device ( 22 ) is adapted to adjust the opening pressure in accordance with the target pressure (P s ) such that it is always a certain amount larger than the target pressure.

What is claimed is: 
     
       1. A coolant system for machine tools having at least one consumer, comprising:
 a pump for coolant, 
 a pressure sensor for detecting an actual pressure (P i ) in the coolant system, 
 a feedback control device acting upon the pump for regulating the pressure in the coolant system to a target pressure (P s ), and 
 a limiting valve for limiting the pressure of the coolant supplied to the at least one consumer, 
 wherein an opening pressure (P lim ) of the limiting valve is variable and the feedback control device is adapted to adjust the opening pressure in accordance with the target pressure (P s ) such that the opening pressure (P lim ) is always a certain amount larger than the target pressure. 
 
     
     
       2. The coolant system according to  claim 1 , wherein the feedback control device is adapted to adjust the opening pressure (P lim ) to a value that has a constant distance from the target pressure (P s ). 
     
     
       3. The coolant system according to  claim 1 , wherein the feedback control device is adapted to adjust the opening pressure (P lim ) to a value that is proportional to a respective target pressure (P s ).